#define TRUE 1
#define FALSE 0
#define INVALID -1
#define NULL 0
#define total_instruction 320
#define total_vp 32
#define clear_period 50

typedef struct
{
    int pn;
    int pfn;
    int counter;
    int time;
} pl_type;

pl_type pl[total_vp];

typedef struct pfc_struct
{
    int pn;
    int pfn;
    struct pfc_struct *next;
} pfc_type;

pfc_type pfc[total_vp], *freepf_head, *busypf_head, *busypf_tail;
int diseffect, a[total_instruction];
int page[total_instruction], offset[total_instruction];
int initialize(int);
int FIFO(int);
int LRU(int);
int LFU(int);
int NUR(int);
int OPT(int);

int main()
{
    int s, i, j;
    srand(10 * getpid());
    s = (float)319 * rand() / 32767 / 32767 / 2 + 1;
    for (i = 0; i < total_instruction; i += 4)
    {
        if (s < 0 || s > 319)
        {
            printf("When i==%d,Error,s==%d\n", i, s);
            exit(0);
        }
        a[i] = s;
        a[i + 1] = a[i] + 1;
        a[i + 2] = (float)a[i] * rand() / 32767 / 32767 / 2;
        a[i + 3] = a[i + 2] + 1;
        s = (float)(318 - a[i + 2]) * rand() / 32767 / 32767 / 2 + a[i + 2] + 2;
        if ((a[i + 2] > 318) || (s > 319))
            printf("a[%d+2],a number which is :%d and s==%d\n", i, a[i + 2], s);
    }
    for (i = 0; i < total_instruction; i++)
    {
        page[i] = a[i] / 10;
        offset[i] = a[i] % 10;
    }
    for (i = 4; i <= 32; i++)
    {
        printf("---%2d page frames ---\n", i);
        FIFO(i);
    }
    return 0;
}

int initialize(int total_pf)
{
    int i;
    diseffect = 0;
    for (i = 0; i < total_vp; i++)
    {
        pl[i].pfn = INVALID;
        pl[i].counter = 0;
        pl[i].time = -1;
    }
    for (i = 0; i < total_pf - 1; i++)
    {
        pfc[i].next = &pfc[i + 1];
        pfc[i].pfn = i;
    }
    pfc[total_pf - 1].next = NULL;
    pfc[total_pf - 1].pfn = total_pf - 1;
    freepf_head = &pfc[0];
    return 0;
}

int FIFO(int total_pf)
{
    int i, j;
    pfc_type *p;
    initialize(total_pf);
    busypf_head = busypf_tail = NULL;
    for (i = 0; i < total_instruction; i++)
    {
        if (pl[page[i]].pfn == INVALID)
        {
            diseffect += 1;
            if (freepf_head == NULL)
            {
                p = busypf_head->next;
                pl[busypf_head->pn].pfn = INVALID;
                freepf_head = busypf_head;
                freepf_head->next = NULL;
            }
            p = freepf_head->next;
            freepf_head->pn = page[i];
            pl[page[i]].pfn = freepf_head->pfn;
            freepf_head->next = NULL;
            if (busypf_tail == NULL)
            {
                busypf_tail = busypf_head = freepf_head;
            }
            else
            {
                busypf_tail->next = freepf_head;
                busypf_tail = freepf_head;
            }
            freepf_head = p;
        }
    }
    printf("FIFO:%6.4f\n", 1 - (float)diseffect / 320);
    return 0;
}
